Most electronic circuits run on DC supply voltages, typically about 1 V to 5 V. To supply these circuits, many methods start with a sufficiently high voltage and use a power converter to step down or up to the desired level. Frequently, a power converter circuit would be connected to a source voltage which provides a startup power and also the operating voltage required to run the power converter control. Typically, a startup circuit is provided to supply the initial power up signal from the source voltage to get the converter running just long enough for it to become self-sustaining. Once the power converter reaches the self-sustaining stage, the startup circuit would no longer be necessary and the power converter operates directly from the source voltage.
The power source could be a low voltage single fuel cell or single photovoltaic (solar) cell, for example, which are potential components of present and future energy supply. While a single cell or similar low voltage power source may provide adequate voltage necessary to operate the power converter in the self-sustaining stage of operation, this voltage level, however, may not be sufficient to initially turn on or trigger the power converter into the operational stage.